Cross sectional depth composition generation utilizing scanning electron microscopy

Abstract

A method for generating cross-sectional profiles using a scanning electron microscope (SEM) includes scanning a sample with an electron beam to gather an energy-dispersive X-ray spectroscopy (EDS) spectrum for an energy level to determine element composition across an area of interest. A mesh is generated to locate positions where a depth profile will be taken. EDS spectra are gathered for energy levels at mesh locations. A number of layers of the sample are determined by distinguishing differences in chemical composition between depths as beam energies are stepped through. A depth profile is generated for the area of interest by compiling the number of layers and the element composition across the mesh.

What is claimed is: 
     
       1. A system for depth profiling a sample, comprising:
 an excitation source configured to scan a sample with an excitation beam; 
 at least one energy detector to gather excitation spectra for a plurality of energy levels to determine element composition and layer interfaces across an area of interest; and 
 a data reconstruction module configured to analyze excitation spectra for the plurality of energy levels at a plurality of locations across a surface of the sample in the area of interest to generate a plurality of depth profiles, with each depth profile corresponding to each location of the plurality of locations in the area of interest by compiling, for each depth profile, a number of layers, the depths and the chemical composition for each of the number of layers. 
 
     
     
       2. The system as recited in  claim 1 , wherein the number of beam energies included are stepped through a set step size. 
     
     
       3. The system as recited in  claim 1 , wherein the depth profile is determined by correlating beam energy with atomic number and/or material density to determine a depth of an interface between materials of different chemical compositions. 
     
     
       4. The system as recited in  claim 1 , further comprising a profile data structure for storing information for the plurality of depth profiles. 
     
     
       5. The system as recited in  claim 1 , wherein the plurality of depth profiles provides a virtual model depicting a cross-sectional view of the plurality of locations of the sample. 
     
     
       6. The system as recited in  claim 1 , wherein the excitation source comprises a scanning electron microscope (SEM). 
     
     
       7. The system as recited in  claim 1 , wherein the excitation beam comprises an electron beam. 
     
     
       8. The system as recited in  claim 1 , wherein the at least one energy detector comprises at least one energy dispersive X-ray spectroscopy (EDS) detector. 
     
     
       9. The system as recited in  claim 1 , wherein a mesh is generated to determine the plurality of locations in the area of interest. 
     
     
       10. The system as recited in  claim 1 , further comprising a display configured to display an image of a cross-sectional structure of the sample as a result of the plurality of depth profiles. 
     
     
       11. The system as recited in  claim 1 , further comprising at least one electronic amplifier configured to detect and amplify current absorbed from the excitation beam by the sample. 
     
     
       12. A system for depth profiling a sample, comprising:
 a data reconstruction module configured to gather energy-dispersive X-ray spectroscopy (EDS) spectra using an applied electron beam for a plurality of energy levels at a plurality of locations across a surface of the sample to determine a number of layers and their composition at each location as beam energies are varied, the data reconstruction module further configured to generate a plurality of depth profiles, with each depth profile corresponding to each location of the plurality of locations in an area of interest. 
 
     
     
       13. The system as recited in  claim 12 , wherein the number of beam energies included are stepped through a set step size. 
     
     
       14. The system as recited in  claim 12 , wherein the depth profile is determined by correlating beam energy with atomic number and/or material density to determine a depth of an interface between materials of different chemical compositions. 
     
     
       15. The system as recited in  claim 12 , further comprising a profile data structure for storing information for the plurality of depth profiles. 
     
     
       16. The system as recited in  claim 12 , wherein the plurality of depth profiles provides a virtual model depicting a cross-sectional view of the plurality of locations of the sample. 
     
     
       17. The system as recited in  claim 12 , wherein a mesh is generated to determine the locations and includes a grid size, the grid size being adjustable such that an adjustment to the grid size controls a resolution of the plurality of depth profiles. 
     
     
       18. The system as recited in  claim 12 , further comprising a display configured to display an image of a cross-sectional structure of the sample as a result of the plurality of depth profiles. 
     
     
       19. The system as recited in  claim 12 , further comprising at least one electronic amplifier configured to detect and amplify current absorbed from the excitation beam by the sample. 
     
     
       20. The system as recited in  claim 12 , wherein the data reconstruction module is configured to determine the number of layers and their composition using a Monte Carlo simulation of beam penetration depth.